DANNEMORA, N.Y. — Investigators are looking into whether civilian employees or private contractors helped two murderers obtain the power tools they used to break out of a maximum-security state prison near the Canadian border, New York Gov. Andrew Cuomo said Monday.

Cuomo said during a round of appearances on television morning news shows that he’d be shocked if a prison guard was involved in the escape from Clinton Correctional Facility in Dannemora, 20 miles south of the border.

Officials said David Sweat, 34, and Richard Matt, 48, cut through steel walls at the back of their adjacent cells and steel pipes while making their “Shawshank Redemption”-style breakout, which guards discovered early Saturday. Sweat and Matt were still on the loose Monday.

Investigators are interviewing hundreds of civilian employees and the contractors who have been doing extensive renovations at the 170-year-old facility, Cuomo said.

“We’re going through the civilian employees and private contractors first,” he said on NBC’s “Today” show. “I’d be shocked if a correction guard was involved in this, but they definitely had help, otherwise, they couldn’t have done this on their own, even from the equipment point of view.”

Cuomo said Sunday the escape was a “sophisticated plan” and announced a $100,000 reward for information leading to men’s capture.

Sweat was serving a sentence of life without parole for the 2002 killing of a sheriff’s deputy. Matt had been sentenced to 25 years to life for kidnapping, killing and dismembering his former boss in 1997.

“These are killers. They are murderers,” the governor said. “There’s never been a question about the crimes they committed. They are now on the loose, and our first order of business is apprehending them.”

Officials gave no details on how the men managed to avoid detection while cutting their way out. “They had to be heard,” Cuomo told ABC’s “Good Morning America” on Sunday.

After the search is over, “we’ll go through the exact details of what they did and how they did it to ensure this never happens again,” Cuomo said later.

Hundreds of law enforcement officers fanned out around the prison, following up on dozens of tips. Authorities set up roadblocks and brought in bloodhounds and helicopters.